On the thermal degradation of poly(vinyl chloride). I. An apparatus for investigation of early stages of thermal degradation

A dehydrochlorination apparatus is described for studies of the early stages of the thermal degradation of poly(vinyl chloride) (PVC), combining good reproducibility, high accuracy, and a low detection limit. The evolved hydrogen chloride is absorbed in water and the electrical conductivity is continuously recorded. Measurements of the rate of dehydrochlorination repeated over an extended period of time showed a standard deviation of 2% of the mean value. The activation energies for the dehydrochlorination in nitrogen for two commercial suspension-polymerized samples were found to be 27.9 ± 1.5 and 26.2 ± 0.6 kcal/mole.